This invention pertains to pseudo-random track selection, and more particularly to pseudo-random track selection in a portable device.
The ability for a person to take a portable form of music with them has been important to most people. Early portable radios, and then the Sony Walkman, allowed people to enjoy music on the go.
With the advent of digitally stored music, the bar has been raised in terms of sound quality for listeners. Compact discs offer a level of quality that records and audiotape simply cannot reproduce. In addition, of late, tracks are being xe2x80x9crippedxe2x80x9d into MP3 format. The MP3 format (formally known as the Moving Pictures Experts Group (MPEG) Audio Level 3) is a compressed format for music. An MP3 file can store a compact disc track in a fraction of the space. In addition, as the MP3 compression format achieves its compression rate by discarding information generally outside most persons"" audible range, the loss of quality is generally very small.
With music stored in a randomly-accessible format, it becomes possible to offer users the opportunity to randomize track playback. (Random access can be achieved with linear-access media, such as audiocassettes, but the time delay in forwarding or rewinding the medium to the next randomly selected track is typically considered crude and unacceptable.) Compact discs can be scanned very quickly to find the next desired track, even though the tracks are arranged in a sequential fashion on the disc. And because each track stored in an MP3 format is a separate file, random access of the files enables random track playback.
In the past, to achieve random playback, a random number generator would be used to produce a random ordering for the tracks to be played. But because the random number generator was invoked when the user elected to play the tracks in a random order, the random track order had to be stored in random access memory (RAM). Because RAM is expensive to include in such playback devices, dedicating RAM to be able to create a random playback order is wasteful.
The present invention addresses this and other problems associated with the prior art.